Final answer:
Sticky rice, also known as glutinous rice, is sticky due to its high amylopectin content, which becomes sticky when cooked. Dextrins, a component of starch, contribute to this characteristic stickiness, making the rice useful for traditional dishes and as a versatile adhesive in various products.
Step-by-step explanation:
What makes sticky rice (glutinous rice) sticky? The clue to sticky rice's adhesiveness lies in its starch composition, which is rich in a type of glucose polysaccharide known as dextrins. These dextrins contribute to the rice's characteristic stickiness when it is wet. Unlike other types of rice which contain higher amounts of a starch called amylose, sticky rice has a higher proportion of amylopectin, which is responsible for the gummy texture.
During cooking, the grains of sticky rice become very sticky because the amylopectin gelatinizes, resulting in the rice clumping together. It is often used in traditional Asian dishes, such as Zongzi, a rice dumpling wrapped in bamboo leaves prepared for the Dragon Boat Festival. The natural stickiness of glutinous rice also makes it an excellent choice for sweet and savory dishes where the rice needs to hold its shape.
Moreover, dextrins are versatile in their usage, not limited to just food. Their ability to adhere upon wetting makes them suitable as adhesives on stamps, envelopes, and labels, among other applications. The digestibility of dextrins also makes them a useful ingredient in commercial preparation of infant foods.